Rule 34(a) · Maneuvering & warning
One short blast
International: “I am altering my course to starboard.” Inland: “I intend to leave you on my port side” — a proposal that must be answered.
You hear: 1 short blast.
Meaning
“I am altering my course to starboard.” An action signal — it announces a turn already being made. Sounded on the whistle by a power-driven vessel underway, in sight of another vessel, when maneuvering as authorized or required by the Rules.
“I intend to leave you on my port side.” An intent signal, not an action signal: it proposes a port-to-port passing when power-driven vessels meet or cross within half a mile of each other. The other vessel must answer — the same signal if in agreement, or the danger signal (5 short) if in doubt.
Key facts
- Sounded by
- Power-driven vessel underway, in sight of another vessel
- Repeated
- Not a repeating signal — sounded when the situation calls for it
- Applies under
- International & US Inland
- Notation
- ·
Related signals
Source: Rule 34(a) — USCG Navigation Rules (International & Inland)
Rule text is reproduced from the public-domain USCG Navigation Rules. Audio is synthesized to Rule 32 timings.